In low-power wireless networks, such as a body area network, a plurality of nodes form a subnet with a hub, which may also be referred to as a cluster controller. The nodes may form secured or unsecured connections with their desired hub. The amount and frequency of information exchanged between each node and the hub varies by time and by node. The nodes and hub designate allocation intervals in which the devices can communicate over a shared channel. There is a need for the nodes and hub to have the capability to use a variety of access methods in order to support reoccurring and one-time communications.
The nodes and hub must also accurately time their transmissions to avoid collisions or overlapping allocation intervals on the shared channel. Accordingly, there is a need for the nodes and hubs to account for clock drift and to synchronize clocks at certain times.
The nodes may operate on battery power and may need to manage power usage to maximize battery life. Transmission and reception of frames over the shared channel are a drain on the power source or battery. Accordingly, there is a further need to manage a node's capability to access the communications medium, such as air, within the power constraints of the nodes.